Raid

In: Computers and Technology

Submitted By narmi
Words 851
Pages 4
Redundant Array of Independent Disk (RAID) is a method of storing the same data in different places on multiple disks. Disk storage space is partitioned to units this technique is called disk striping. Storing the data on multiple disks improves the performance because the operations are done and overlapped in balanced way. Storing data redundantly on multiple disks increases fault tolerance.

Data that are stored in multiple disk and they are accessed parallel to achieve.

* Large data access by higher data transfer rates.

* Small data access by higher I/O rates

Some of the different types of RAIDs are discussed below.

RAID Level 0:

This has non redundant disk array and less cost to the organization because it does not have redundancy at all. It is thought that this has better performance; it does not have to update redundant information. But it does not, redundancy can perform better by scheduling request in the disk by selectively with shortest seek and rotational delays. If there is no redundancy data will be loss with single disk failure.

RAID Level 1:

This uses the solution called mirroring and uses many disk that non redundant array disk. Whenever data is written to the disk it is also written other redundant disk it has always copies of two, so data is not lost because of single disk failure it can always request for other copies.

RAID Level 2:

This is memory style and provides less cost for the failed component than mirroring by using Hamming codes. Data are stored in parity disk. In this method five disk require four redundant disks, 1 less than the mirroring and because of this storage efficiency increases.

RAID Level 3:

This uses one drive to store parity information. Errors are detected by embedded error checking the information. Data recovery is done by calculating XOR (Exclusive OR operation) of the…...

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